Please help with this (1958-62) Mil.3818A Bulova - Franken?

Needing the help of our Bulova warriors please.

This 3818A Bulova has me thinking that either the case back or the dial has been replaced.

I believe that there are three versions of these watches and so going on the dial alone I believe this is the third variation the Mil-W-6433A Type A17A: which is the watch issued to pilots and navigators and not ground crew. If that supposition is correct then shouldn't this particular dial have on its case back the engraving "Watch Navig."



photos below are of my watch. What do you think? Franken or did some of these dials have non Navig case backs??



Thank you in advance.

If you got the book Military timepieces by Whitney on page 538, they have 3 of them, with very little info no case back photos just the front photos and the description of what's on the case back, 2 have what you have on case back but have the first type hands the one with Watch Navigation has the type of hands you have with Watch Navigation on case back. Maybe the military in a service switched your hands out in a service. Here is mine.

I only have the 3818 but if I recall they had different movements, a 7 jewel non hacking for the 3818 and 17 (?) hacking for the a17. One would hack and one wouldn’t. Or was that just in the Hamilton 113 vs the field watch?

Considering we have no clue of its service history either in the service or in the years after, we can only speculate- I wouldn’t be banking on some rare military variant.