Mick
All TM 1971 - 1975 tanks were steel - however the RH 74/75 and RN were alloy and are very easy to spot as they have 2 holes for a 6mm screw at the rear. RM125M/S were steel then alloy for the A B and plastic for the C, the 250 / 370 AB were alloy
Hope you have found a rare one!
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