Another day same question/problem.
A little bit more searching and reading here, would have brought up the solution to both of your questions.
The missing version-main is a damn well known Bug of some TWRP versions. By flashing those versions the version-main entry is deleted. Glad that I took a note of it before I flashed TWRP myself.
Second if you were stock all the time and still are you're good to go with a stock recovery corresponding to the version number in settings > about phone > software information > software number.
Sent from my HTC One_M8 using XDA Free mobile app
Mobile: One M8 Gunmetal: UNLOCK - S-OFF (SunShine) - WWE
CID: HTC__001 (T-MOB101)
FW: 2.22.401.5 (184.108.40.206)
ROM: Stock - SuperSU
Retired: Desire (CWM, Cyanogen), Sensation (Unlocked, S-On, CWM, root), One X (Unlocked, TWRP, Cyanogen), One (M7) (firewater S-Off, TWRP, ViperOne), Moto G (Unlocked, S-On, CWM, CM11), One (M8) GER Silver (SunShine S-Off, TWRP, ViperOne 2.2.0).