Hey Giz,
You have a mid run Rotomo 2 as it stands.
58,000 Serial will be tin wheels(circlip axles) on model 2 chassis. Axle mount height will be 20mm.
Engine will be Victa stamped and use the larger champfer Top hat pulley.
Carby is model 2 non brass nut circlip style.
Muffler will be std bun central convex style.
There are only 2 genuine rotomo mufflers. Model 2 central bun with convex outer(common) and model 1 central convex (same as model 2 style but wider)
All Rotomo mufflers are convex, the concave effect you see often is merely a colapse from heat over time.
The 3 remaining muffler types are reinforced central and reinforced offset and std offset.
Offset mufflers were not intended for rotomo, but used on Generic/store models that required height clearance. EG, HG Palmer Utilities.
Both reinforced mufflers could be either late OE replacements or After market.
To Simplify, yours uses the std bun, non reinforced central convex.
Model 2 Victa badge. (Straight 1 on the 18) curved 1 is model 1 badge.
Throttle black plastic Victa marked
Fuel cap tin
Filter choke, Small 3/4 mounted white top adjustable Red Victa smiley face
snorkel straight
2 cable mount clips
2 alloy snorkel mount ties.
2 piece spark plug
Model 1/2 fuel tap.
In regards to axle mount height your will be safe and accurate at 20mm.
The larger mounts were predominantly found on model 3, but have been seen sporadically on model 2s, possibly due to supplier or availability problems.
Let me know if this is suitable, and ill post some pics of correct parts.
Im sure I have an accurate 2 in the Victa or rotary forums, you can check.