the changing part numbers and small variations between similar coils is just something to put up with .. or take advantage of.
C-2794-303 is the early part number. Shoot-A-Line and Lite-A-Line manuals had it, and those are the same time frame as the screen games (except Malibu Beach). That number was still used on Bonus 7 in 1970, and appeared occasionally in manuals up to that time.
FD-30-1300 was used on most games after Bonus 7, starting with Stock Market.
if the manuals are right ... and that's a big if on the 1970's game ...
EA-29-950 was used on Ticker Tape in 1972. Same as the search index coil.
ED-30-1300 was used on Miss America Supreme - probably a typo
to further confuse things:
E-184-248 new part number was FC-30-1300.
difference between FC and FD ... dunno. The format of the "new" style numbers is:
bobbin id - wire gauge - number of turns of wire around bobbin
besides the obvious size and shape differences for the bobbin there was stuff like location of the lugs, right angle bends on the lugs, the metal on top of the coil, did it have an embedded brass washer to reduce magnetizing the bracket, etc.
I've never seen a document that decodes the bobbin prefix.
fwiw, any of the above coils would likely work in any game except an EA-29-950. On a game that the coil would stay powered as long as the button was pushed, you'd have an embedded toaster. Most games would be fine with an EA-29-950 because a switch on the locking cam opens when the search wipers are released and disconnects the coil almost immediately. That switch was not on County Fair or previous games, but it was on the next game Laguna Beach.