Hi Grizz, your dissy looks like a 45d as there isn't a vernier adjuster on the opposite end of the advance and retard assembly.
Also a 25d has a nut which the condenser wire and the low tension wire
attach to on the points but a 45d has a spring clip affair which does the same job, hope this is of help to you,otherwise it means cleaning the outer casing and looking for the number which is stamped on the outside.
All the best
Trev
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