Parker Chomerics -77 suffix specifies PSA or pressure sensitive adhesive on their Pola Sponge series of gaskets, which is usually a special order option.
Datasheet:
https://www.parker.com/Literature/Chomerics/Parker%20Chomerics%20POLA%20SPONGE.pdf
Part numbers that may be specially ordered with adhesive:
07-0201-0875
07-0201-0237
07-0202-0094
07-0201-0090
07-0202-0488
07-0202-11053
RFI and EMI - Contacts, Fingerstock and Gaskets is the category these are found in.