The Trumpeter T-55 et al series is a jumbled affair with a multitude of variants coming within virtually all the same basic kit. Really, from what I see is the basic difference is the main guns and knowing what unused parts from one set of instructions should be used on the variant you want to create.
I know they retooled the turret on later kits (which is why my later T-55 has a separate turret sprue).
You are better off with the very good Tamiya kit, but don't worry about your kit; just start building it. If you want, send me your email address and I can scan my T-55 pages so you can make your Type 59 into a T-55. You may have to find an aftermarket barrel, but the one on your Type 59 may be the same one.