No, it just was badged a 350SL.
The 450SL went into production in July 1971, and was only available for the North American market until February 1973.
But the car was still badged the 350SL, perhaps because of the relatively small amount being produced they didn't bother making the 450SL badge until it was available elsewhere? Not sure why yet, maybe I have a 73 intro book which will explain it, or the 72 intro book can shed some light.
According to my disc, the 450SL for the North American market was a low compression engine to meet emissions in the US, 195 hp it says.