A nickel under every bottle cap ???

Seems pretty unlikely to me, for two reasons.

"Uncle Ben's" (forgot what the official name of that brewery was) was not a microbrewery, where some beers might be bottled by hand, but a small regional which would have automated bottling/capping, one would imagine. While the speed of such machines might not be up to Molson numbers, I can't see how a nickel could stay on the bottle for accurate crown capping.

And, even if it could stay on the bottle top, centered correctly, the standard crown cap could not make a perfect, air tight seal with a nickel under it and I rather doubt that a brewer would order non-standard crown caps for such a give-away or bottling equipment could handle anything other than a standard crown cap.

When Uncle Ben's was in business, the crown capped (i.e., non-twist off) stubby bottle was still standard in the Canada, IIRC.

It has been a long time but my few surviving memory cells tell me that Uncle Bens which had started in BC had opened in Red Deer moving into the Alberta market and there was a dispute over pricing and they taped a dime inside each case of 12 sold. Remember a case of 12 was under $3.00 in those days.