Well, all the NCC numbers actually seen in TOS were within a fairly narrow range, between 1664 and 1887 at the very most (both numbers taken from the "Court Martial" chart and applying selective squinting at the ambiguous 6s and 8s). In comparison with those, NCC-1017 would really be out of whack. The implication might be that Decker's ship is a relic, launched about halfway between the founding of Starfleet (whenever that was) and the TOS era.
However, TOS-R adds a few low numbers for variants of the transport (drone) design borrowed from TAS and first seen in "Charlie X"-R. Some of these may even be discerned on screen, although again only with heavy squinting. In that context, NCC-1017 isn't quite that bad any more.
Whether the Franz Joseph scheme, with the 500-range scouts and destroyers, makes any sense in either context is debatable. It's not supported on screen much, as the FJ graphics we see in the movies don't flaunt registry numbers.