No... those two chips are very different. Someone could create (and perhaps already has) an adaptor board that uses that NVRAM to replace a 5101.
If you're looking for a plug-in replacement for a standard SRAM (6116, 6264, etc.) you need to find the Simtek of the same density that uses the standard JEDEC pinout. The spec sheets for the Simtek chips are all on the Cypress website now.
Yes, Mark has a 5101 replacement that uses Simtek. Unlike the Tom Callahan version (link in previous post), Mark uses a 25C48 (now obsolete) or a BRAM.