Probably more than it's worth if you do it yourself, definitely more than it's worth if you pay someone by the hour to do it.

You'll need a RHD car for all its parts. I understand it's much easier or at least possible to bring a European or Asian market car into Canada than into the US. There might be a cheap hulk of an ex-taxi 124 in Malaysia or Indonesia that you can bring in for parts.

See if one of the shops that imports surplus Japanese engines can bring in a W124 front clip for you.

Sixto
91 300SE
87 300SDL
83 300SD