Part number with '77' prefix?

[shrtrnd]

Got two 14-Pin DIP's I'm trying to identify:
SGS 7709393
Fairchild 7709393
I was leaning toward the old Fairchild FU5B series, but am confused by the SGS chip.
I've got some old Fairchild FU5B77xxxxx, but they're all in can packages, no DIP's
Is anybody familiar with either of these devices?
Thanks

 

[woodchips]

709 opamp?

 

[(*steve*)]

how are those identifiers laid out? It could make all the difference.

 

[shrtrnd]

I don't have the IC's with me at the moment. But I'll recheck them later.
I found a website (reliability unknonw) that crossed the following simiilar parts:
FU5B7710393 = 710HC
FU5B7749394 = 749HC
As you can see from the 2nd, 3rd, & 4th number characters in the string, like woodchips
noticed, the logic would seem to be that my questionable devices should be LM709 Op Amps.
I'll probably build a test circuit to test that theory sometime.
I'm still curious about the whole FU5B77xxxxx numbering system, don't know how
it originated, or the rational for it. Maybe some kind of miliary designation?
I'll come back to this when I take a closer look at the chip identifier lay-out, and post
it here.
Thanks for the feedback.

 

[shrtrnd]

Here's the update on the identifiers on the IC's above:
(Fairchild Logo) 7709393 (first line)
U6W (Date Code) 7035 (2nd line)
It's a gold plated ceramic 14-Pin DIP

7709393 (first line)
SGS B (Date Code) 7418
It's a plastic package 14-Pin DIP

That's all that's on the IC package.