So many replies. And no replies to this.
They probably felt little need to match the Starbase 11 chart since it was only some crazy kid years later who associated all of those numbers with ships like the Enterprise, and of course Republic 1371 was a starship in dialog so lower numbers were perfectly fine.
I just came across _
this Flickr image_ of a shot of Constellation 1017 purporting to be from a cleaned up film source. A few things stood out.
1. The spacing between characters for U.S.S. was inexact, and CONSTELLATION seems to change angle a bit at the A.
2. More importantly, I'm not quite sure U.S.S. CONSTELLATION has the right typeface. The font chosen appears to be a close match but seemingly lacks the blocky 45-degree cuts of the Enterprise name on the Enterprise models. Note specifically the S, whose center appears to aim downward ( like \ ) rather than straight across.
Based on _
this old scan_ of early AMT decals it definitely isn't a match despite the availability of enough letters S, and comparison of the late version of the font on the 11–foot and the Constellation appears to support the idea that the letters are also taller / less wide, with lower line weight.
I propose, then, something akin to Tomalak:
They had to stencil the new name by hand, but could simply use the existing decals for the number, which they did in the easiest way possible - they didn't even make one additional cut and number the ship NCC-1710 which would have saved us all a lot of heartache! But it could have been worse - they could have picked 7011.
That is to say, they used a transfer or stencil technique for the Constellation name using a close-enough typeface, but they either didn't have the larger size needed for the registry or were concerned about it not matching well enough, so chopped up the AMT decal in a pinch. If they'd had two, 1717 would've been possible, but that wasn't the choice.
1710 was probably considered and disregarded as too close, especially if they weren't close enough for the name to be easily visible. Paint-matching the look, finish, and size of the AMT decal with a new digit would have taken a fair bit of time ... maybe they'd have had the time for that or some other painting if the writers hadn't have picked the longest-ass name for the ship for them to have to letter, not to mention having to ensure they had a paint that would stand up to the lights and not also eat the plastic.
Perhaps they also discussed trying to damage the model at the registry to render it unreadable, but this would have been considered and discarded since they still would've needed lettering visible beneath the burn and it would've burned weirdly.
Back to the point, though, short of some sort of kitbash of the parts, they distinguished the ship as best they could, all while ensuring it remained a clear sister and equal to the Enterprise.