The GX-55 was a plug in GPS replacement for the LORAN units.
As I understand it, the GX-50, GX-55, GX-60, and GX-65 all take the same database.
I had a Jeppesen database subscription for my GX-60 that I let expire in March. I was not flying IFR to justify the expense.
In April, Jeppesen still sold updates. IF you would want an old database from early this year, I may be able to help. I have about a dozen cards that had old databases on.