Not quite correct

PC66, 100, 133 all follow the exact identical design layout. The difference is that in the old days, a 16 MB DIMM was a huge thing. The width of the chips has not changed much, that is, they used to be x4 and are now x8 (16 chips for a double sided single bank as opposed to 8 chips / bank & side) but that only required 2 M addresses whereas we are at 8M or 16M now.
Address numbers are the multiples of row x column and for 2M you need 2k Rows with 1k columns or 10 address pins whereas the new controllers have 11 or 12.

That's the only issue and if you plug a new module in, the address select pin terminates in a no-connect on the socket and won't get any signal (which is why you don't see 3/4 of your DIMM)

Only thing you can try is to get some really old DIMMs, Coast-to-Coast has all this stuff lying around