Igorrock, I really can't say for sure the Fraser rifles did not have a slant box magazine.... However,the bottom metal on the Fraser rifles appears to be exactly like the standard military version. The floor plate is directly below the action, and not set back rearward as in a slant box magazine. The Rigby models and Siamese Mauser have a floor plate slightly more to the back because of the box slanting rearward.

Here is the Hollowell gun :
http://www.hallowellco.com/danl%20fraser%20360.htm

Wyatt