The 1665 looks aftermarket, but impossible to tell based on such (purposely) crummy pics. Ask seller for good, clear macros (without glare, shadows, blur) of the movement, dial & caseback. Post them here (if you get them) & we can provide more specific answers.
As for the 1675, I would not buy watch parts from a seller with less than 200 previous high-end watch-related auctions & at least a 99.5% rating.
Always, buy (investigate) the seller before you buy the.....