Front: Bulova / Self-Winding Back (clockwise, from top of case): BULOVA / Stainless Steel Back / Anti Magnetic / Shock Resistant / Self-Winding / [star] Water Tite [star]
Yes, the face is identical to the 1955 Royal Clipper, but it's the back that threw me off because the serial number isn't in a box like the Royal Clipper has it. I haven't been able to find an example of a similar model that has the serial number on the back, outside of the boxed text in a circle.
The winding pin is not original, but the rest is (to the best of my knowledge).
I am unable to match this case and dial. I first thought American Clipper, but the lugs here look wider. The dial is Clipper similar, but other models during the 50s used this dial design. I am hesitant to call it a Clipper, and would go with Unknown at this time.