The 52 is the better horn, then.
I don't disagree with Nissan...the $1150 is a store/shop pricetag. Store pricetags are grossly inflated above actual market values. There's a "convenience fee", sure, and far be it from me to dis' the concept of buying from a local shop, because I think that's awesome. However, an 70- 90% markup over actual value :tsk:.....is not awesome.
You didn't say this was being sold at a store...so we dunno if it is a private seller or a store.
If the horn is in really good shape, no dents, all pads sealing up and down, and the store will run it by their tech one more time before you walk out w/it....and it comes with a return policy....all of that might warrant $1150.
But if the horn has any significant dents or its pads are sorta iffy....no way in heck is that a reasonable price.
If the horn is being offered by a private seller, then at tops $900-1000 is what is a reasonable price to pay.
If the 16M had been a pre-mid '70's one, I would have gone for that. But those late 16M's are not in the same league as a 52. Conn was nary even a shell of their former glory by then, sadly.
Best of luck !