...the Product number and FID are the same [TOPO U.S. 100K v5; P/No 006-D4339-00; FID 2837] indicating that they are the same map but compiled differently.....

That nails it! Catymag did explain, but there were these unexplained "conflicts" re header dates, versions, etc...that prompted me to ask (for clarification). I have seen P/Ns by manufacturers used loosely as well (form fit function, but maybe not content)....and...
It is interesting that some people are selling a "new" version of this mapset as a DVD with a P/N 010-11001-02, but garmin doesn't list that, it shows 010-11001-52 for the DVD, the download (010-D1309-00) and SD card version(010-C1098-00) have different P/Ns.....and Garmin most importantly doesn't seem to identify an actual version or date of change....
It is almost like the streetmaps that are clearly identified with a version are made by a different company.

So the question of the crc error can rest, since I already have FID 2837...