A picture of the stock Drop ALT layout. The bottom modifiers are 1.25u keys. The right shift is 1.75u (red means atypical). The far right column is red because those keys are typically on different rows (being compared to a standard TKL or ANSI 104).
This is significant because keycaps like Cherry, OEM, MT3, and SA are non-uniform. That means that different rows on the keyboards have different side profiles.
This post by RedSuns is really good. View the images and row profile identifiers for the different kits of GMK Red Samurai to picture how the keys have been moved around to accommodate for the 65% layout.
https://drop.com/buy/drop-redsuns-gmk-red-samurai-keycap-set/talk/2450958?utm_source=linkshare&referer=BPKDQH