Before the "doghouse" style oil cooler came along, the air blowing across the cooler was directed down onto #3 and 4 cylinders . . . it did not exit out the back of the fan shroud.  The tin shown in the top of the picture would not have the big rectangular hole in it and the other pieces wouldn't be used.  If it's still the original 40 horse engine, the tin is also slightly narrow compaired to the 66 and up tin.

. . . but it was chrome. Unfortunately it doesn't seem to fit . . .

With aftermarket stuff, there is no telling.  If it's EMPI (the new stuff, not the REAL EMPI stuff from the 60's and 70's) it probably needs to be trimmed, bent, twisted, hammered, cut, split, bent some more, hammered on some more then thrown in the garbage.  The last time I bought a piece of EMPI tin (the type three style lower cylinder baffle) I had to cut, trim and bend it to get it on . . . by the time I got it to "fit" it was broken in half and I had to tie the pieces together with mechanics wire.   There may be some good aftermarket chrome tin out there, but I've had my fill of the cheap stuff.  A beat up rusty piece of original German tin might look like crap, but it fits and gets the job done.