I occasionally do work on Guam and CNMI and have worked with archeologists and the State Historic Preservation Offices (SHPO) there. I‘m sure they would be interested in these photos and could probably tell you something about them. I would start by contacting the SHPO on Guam. They may even be interested in using copies of these images for their own archives. You could also contact the museum, they recently built a very nice new museum there and are very interested in preserving their history.
what information do you have that makes you believe they were taken on Guam?
If you don’t get anywhere with either of them I could get in touch with an archeologist I’ve worked with there but I think you will probably get a positive response from the SHPO.
Guam SHPO
Guam Museum