If that is truly a V5, then the thin cradle is a big surprise. That cradle was used in in the mini, V2, and the 1st generation V3 (up
through late 2013 or so). The 2nd generation V3 introduced the larger cradle. All 2nd gen V3's as well as the V5's we've seen have always included the larger cradle (the V5 originally came with the new cradle beginning with it's initial release - as far as we are aware). The screen display used on the board from your pic is what indicates to me that this is not a 1st gen V3, since they used an early version display that used a foam block that was sandwiched between the circuit card and the thin display.
Something else that's curious is the clear outer button I can see in one of your pics. So far, (on this thread) we've only seen the stainless steel metal button or the chromed plastic "power symbol" button on the V5's.
Maybe
sigelei had a bunch of spare parts laying around and decided to use them (V5 circuit card, V3 1st gen cradle, V3 clear button, 2nd gen V3 or V5 body).
I wouldn't be too concerned about the smaller cradle or the clear button in regard to function. The smaller cradle works OK, but I would seriously consider installing a 2mm spacer under the top cap as additional
insurance against circuit card shift (IMO it's always a good thing to do regardless). The clear button is probably a better choice over the chrome plastic button anyway. At least you don't have to worry about the chrome wearing off the plastic button as others have reported.