Get some training or practice
FAR's don't cover everything. Sometimes common sense kicks in. To me the intent is if you DON'T HAVE experience in something, endorsement or not, you need additional training and practice. It does not necessarily have to be from a CFI. A RV with a constant speed prop is not complex by FAR definition, but by my definition it's complex. If you never used a constant speed prop, 1st flight would no be the time to learn.
The first C/S prop / complex plane I flew was a Piper Arrow. It took me a few hours to get comfortable with the prop control. It took another few hours before it become second nature. You really don't want to have to use to much brain muscle to manipulate the prop control, which does take SOME finesse.
YOU don't want to be a test pilot and have to be thinking about, "Now do I move the prop control first or throttle first?" You should not be learning how to fly the prop on your first flight.
If you can find a complex training device or simulator to practice that might give you a level of comfort. Other wise find a plane with a controllable prop and go fly with someone, the pilot/owner a rent a plane (C182) with a CFI. Best of course would be some actual RV stick time with a C/S prop.
I learned, never to quote regs from memory:
************
Part 61
(e) Additional training required for operating complex airplanes.
(1) Except as provided in paragraph (e) (2) of this section, no person may act as pilot in command of a complex airplane (an airplane that has retractable landing gear, flaps, and a ** controllable pitch propeller; or, in the case of a seaplane, flaps and a controllable pitch propeller, unless the person has--
(i) Received and logged ground and flight training from an authorized instructor in a complex airplane, or in a flight simulator or flight training device that is representative of a complex airplane, and has been found proficient in the operation and systems of the airplane; and
(ii) Received a one-time endorsement in the pilot's logbook from an authorized instructor who certifies the person is proficient to operate a complex airplane.
(2) The training and endorsement required by paragraph (e)(1) of this section is not required if the person has logged flight time as pilot in command of a complex airplane, or in a flight simulator or flight training device that is representative of a complex airplane prior to August 4, 1997.
(f) Additional training required for operating high-performance airplanes.
(1) Except as provided in paragraph (f)(2) of this section, no person may act as pilot in command of a high-performance airplane (an airplane with an engine of more than 200 horsepower), unless the person has--
(i) Received and logged ground and flight training from an authorized instructor in a high-performance airplane, or in a flight simulator or flight training device that is representative of a high-performance airplane, and has been found proficient in the operation and systems of the airplane; an
(ii) Received a one-time endorsement in the pilot's logbook from an authorized instructor who certifies the person is proficient to operate a high-performance airplane.
(2) The training and endorsement required by paragraph (f)(1) of this section is not required if the person has logged flight time as pilot in command of a high-performance airplane, or in a flight simulator or flight training device that is representative of a high-performance airplane prior to August 4, 1997.
************
Endorsement or not, I think you should get some experience / training if:
Never flew a RV
Never flew a stick
You're not current flying
Never used a constant speed prop
** FAR's are getting old and new to be updated to keep up with 'Complex', 'High-Perf', FADEC, EFIS. Planes with FADEC do not have controllable prop or mixture. Can you use a FADEC plane for a commercial pilot practical test, which requires a complex plane? Yes. But its not in the FAR's. The FAA has FAR guidelines to clear up the grey areas. If you are concerned call you local FSDO and confirm you are good to go with out a endorsement.
Another example, you get your private & IFR rating in a '07 C172 with Garmin 1000 EFIS, and it's the only plane you have ever flown. Can you just jumping in a 6-pack steam gauge 1978 Cessna 172 and blast off IFR/IMC. The opposite scenario is more likely. You never used a Garmin 1000. Would you go fly IFR with out practice/training on that EFIS? There is no FAR limit on flying a IFR C172, in IMC even if you never used that type of flight instruments or avionics. THAT WOULD BE DUMB.