In the re-marking of a (Ruger) 458 Win barrel to 450 NE, what would be the most 'proper' or historically accurate nomenclature?

450 NE, 450 Nitro, 450 Nitro Express ?
Should a decimal be used before the 450, i.e., .450?
Should the 3 1/4 inch designation be used, or is it understood, since it won't say #2?

Thanks. Just trying to get it right.

I think 450 3 1/4" Nitro Express would remove all doubt about the proper shell to use.
My 450 No2 is marked simply "450 No2"
My 450/400 3 1/4" Is marked "450/400 3 1/4" with the load info also on the bbl.

In their day, "450 Cordite" was also common nomenclature.

My retro-.577 double was made in the late 1990s on a Greener E17 shotgun action, yet the 'maker' had enough good taste to stamp the cordite load and maximum bullet weight on the barrels.

Looks great I reckon!