Hello, like R8lover say's it's a Fiat x1/9 and not a Bertone X1/9, Altough all body's of the x1/9 were built at the Bertone factory. But the one above is a 1300cc 4 gear model, recognisable by the engine cover (also recognisable by the bumpers but they're missing on the pictured model) these were built from 1973 till 1978 and sold under the Fiat name. in 1978 the 1500cc 5 speed model was launched and built by Fiat till 1982. Somewhere in 1982 Fiat stopped with the X1/9, Bertone kept on building them under The Bertone name from 1982 till 1986. Like i earlier mentioned The X1/9 bodywork was designed and built at the Bertone factory, mechanical parts were mounted at the Fiat Factory. From 1982 when it became a Bertone X1/9 the cars were finished completely at the Bertone factory.
The only thing the Stratos and X1/9 has got in common is that they were build at the same time in the same factory.