isobuster renamed my backup files as zip

used isobuster to recover all my files off of my CD but renamed all files esp my genie backup manager files with the gbm ext to regular zip files how can I get them to work under my Genie backup program the zip shows they all seem to be there bu not sure that GBM will read them again just by placing the ext back again has anybody else had this problem and what dids you do to resolve it?