Looks like a great fit to the 16KP4 (or similar) crt... wonder if Motorola got a bit carried away using the "17" in the model number for the newer cabinet? Bet a 17BP4 (or similar) would not match the mask as well.
I would do it without hesitation!!!

jr
Update:just dug out a Sams #167 folder 13 (5-52) for the model 17T5E,F (as well as the 17K10E, 17T6G) chassis TS-314A,B,TS-315 A,B... and the jug is shown as a 17HP4,17TP4... wonder why your 16" fits so well?