The RAM address in that screenshot should be C088. So, C088 should be the pointer value.
You can't easily convert from offset in a .FDS file because an FDS game is an image with several files inside. Files get loaded to RAM (which is where the games are run from), and so the pointer depends on WHERE in RAM that data gets loaded to (that RAM address is in the file header, if you can find the header in the .FDS).
I'm not 100% but it SEEMS that files in an FDS image are stored sequentially and they seem to always have filenames (8 characters) in ASCII (at least the games I have looked at). If I recall, the header format was: a 0x03 flag, 8-character file name, file size and RAM offset (2 bytes each, maybe not that order), then 1 byte indicating destination RAM (PRG-RAM, CHR-RAM or PPU), then a 0x04 flag then the file data.
Without using a tool to rip a file list from the FDS, you'd have to scan through the file to look for ASCII text (for the filenames) and do math using the file size data to find where the files are. Or use the FCEUX hex editor to find the RAM offsets to find pointer values and then do a hex search to find those.