I try answers:
They stopped production I think about ten years ago.
I agree with you, adjustable center pin in the bottom plate is simple and very useful, it enables small circles (6 cm diameter), I can’t do it so easily with festool of. Gamma is very light, too. A slot in the base is very simple and useful but for manufacturers not good!
I think my router is the last one produced, with many new features, the first base was different
Originally the manufacture was Zinken, not Gamma Zinken. Mia 6 and ZC compact 21, as Gamma7, were Zinken products, all made in Italy. I have no news about Zinken, I think the firm went bankrup. Now in Italy there is Gamma Zinken that, for few years, produced Gamma7 and, I think, the others. Now Gamma Zinken market Jet, I think China imported. You can find also router bits gammazinken, products of good quality I think made still in Italy. Now for Italy manufacturers is not possible compete with China, also in Italy you can buy a Chinese router for few euro (20-30-40), low cost and low low quality. You can buy Italian bits and so on but the price (and the quality) is hight. My gamma7 is inexpensive, the last in the store only 95 euro, but it was pure chanche.
I’m sorry what means cast? Iron cast? Base plate and accessories alluminium
Thanks, and you know…… my English is bad