Is this just body fat or do I have gyno? (photos)

Great question. Gynecomastia may be composed of both glandular tissue and fat in the breast. The best option may be gynecomastia surgery. Best, DR. Karamanoukian 

An inperson consultation would confirm what this would be howeer I would suspect it's glandular tissue rather than fat, judging from your otherwise muscular structure.