You are no longer required to have a GROL to program radios, however, the licensee is responsible to ensure his/her equipment is operating within their emission mask, bandwidth, deviation, etc. Proper verification of radio operation with a service monitor can save headache down the road.
MURS and GMRS radios are both license by rule under 47 CFR part 95.
eCFR — Code of Federal Regulations
Technically, a radio has to be certified as a part 95 for both MURS or GMRS, the exception are "grandfathered" part 90 devices on MURS channels which were licensed before the service was created. There is much debate about the legality of using part 90 gear on GMRS part 95. IMO a rule clarification needs to be set on this, as under part 95 rules, if a transceiver isn't part 95 certified, than using a part 90 radio is no different than using a modified ham radio on the band in the eyes of the OET.