All PLCC Eprom/Flash have 32 pins.
The pinout format changes for devices 1M and up.
PLCC 27256/27512/27010/27020/27040 all have 32 pins.
In the dual-in-line format (the socket on the programmer is dual-in-line),
chips up to 512Kbit have 28 pins, and 1Mbit & up have 32 pins.
M3920 PLCC Adaptor
An additional adaptor is provided with the M3920 PLCC adaptor, which is fitted
on the bottom.
This changes the pinout to the 28-pin dual-in-line format for use with 27512
and smaller parts
for the socket on the programmer body,
and adjusts the pinout.
(There is a 28-pin PLCC format, but Eprom/Flash parts do not use this. )