Yep, the part on eBay is the same part as the ones I have, but so far, I've found nothing online that even mentions the basic function, certainly not a datasheet.
And vtech's suggestion for the other part seems to be on track; it fits the package description and marking. I'll check it further after the weekend when I can get access to the proper test equipment. Thanks for pointing me in the right direction. I had tried to find an old TTL 74/54 part with the H81AD number, but no joy with that approach. I was thinking that the F1071 was a date code of sorts, but nothing in Fairchild's old databooks helped with either approach.
Thanks, guys for the help,
DaveM