Yes. The older 4-bit and 8-bit Macintosh video cards (661-0376 and 661- 0492,
respectively) are compatible with all Macintosh II series computers, including
the Macintosh IIfx. They're also compatible with the Macintosh Quadra
computers.
Here's some additional information that might be useful. The older style video
cards do not have sense line capabilities. This means that, when more than one
older type video card is installed, the Macintosh will start up to the card
nearest the power supply NuBus slot. Or, when older type video cards are used
in combination with later version video cards, the Macintosh will always start
up to the older version video card, regardless of NuBus slot positioning.
The older style video card takes precedence because of its lack of sense line
capability.