GMR-1 dissectors, like GSM-A dissectors, can be seen either as separate protocols belonging to the same family, or as a single protocol with sub dissectors:it depends a bit on your point of view :) Personnally I see them as a single one (like Sylvain) and was rather happy with the '.' separator instead of '_' one.
For example at the beginning in Wireshark there was a single packet-gsm_a.c file that became huge and was split into several files in r25915 and r25917.
When looking at
checkfiltername.pl script, it looks like there are already variants allowed for PROTOABBREV ('-' vs '_' for example). Would allowing '.' vs '_' really be an issue? If think it would make sense for big protocols like GSM or GMR-1 (and there is maybe a few other ones). If accepted, we should be careful when reviewing patches to ensure that this capability is not used without any valuable reason.
Regards,
Pascal.