Yes. several. Some appeared to be manufacturing efficiency changes, such as different tube lengths, threading lengths, etc.. Some cosmetic, such as different valve knob size and knurl patterns. And some were primary internal component changes, such as rubber seal vs cork seals; and most recently the orifice (previously referred to as a replaceable spud) which meters gas flow.
Better? Long time users swear by the older 'more adjustable' models... and seek out garage sales for them. Newer users do not have that frame of reference and just use what they get - and based on their results... they get quite a lot and produce truely outstanding beads with it. So 'better', is like 'pretty'... in this case... its' in the hand of the holder.
There are surface visual cues. The earliest models had a tapered neck to a shouldered main body and knurled brass knob fastened on with a screw. There are internal parts cues, including seals, orifice size, sintered pressure reducer, etc. - but to get to those requires disassembly and can affect torch performance. The newest model has 'no user replaceable internal parts', and disassembly is discouraged.
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