frankenstein, but sometimes that's a good thing if it makes the game more interesting.
the serial/model number plate is not reliable as aftermarket sellers/refurbishers commonly swapped plates around or changed what was inside a cabinet to make a different game.
in this example, at least the cabinet style matches an 873-A.
conversion to different denominations is pretty straightforward, tho a professional refurb shop would do a nicer job changing the artwork for the new coins.
assuming the guts of the machine are all electro-mechanical, conversion to hold-n-draw is mainly the addition of a bunch of parts to the reel mech and a couple added relays. More likely a reel mech from a hold-n-draw machine would be swapped into the cabinet. The glass doesn't appear to have any information about hold-n-draw.
it's also possible the buttons are for skill-stop where the player can push the button to stop the reels, but that's even more changes than hold-n-draw.