I seem to recall that the 64 bumper USA and Canadian bumper for wagon rear only, had the same bracket hole spacing. We were originally going to order a new one from the states but decided to have our straightened and re-chromed for half the price. I am thinking the Canadian and US had specific brackets to make the bumpers interchange.

The 64 wagon had a specific rear bumper as it has the extra holes by the reverse lights for the steps. also it does not have a curve in the center. I am not certain on the 63's but would bet that they are all pretty much the same as they were so close.

check out this link. he has some brackets. I have also contacted them in the past and found items not yest listed on their site. He supplied me some chrome for cost of shipping only that came off a wrecked car. We were able to get them straightened and are now on our car.

https://frankspontiacparts.com/usedparts2/fullsizepontiacpartsp2.htm

My 63...is a driver survivor.....and just doing some clean-up in the tailgate and rear bumper areas...

It appears there may have been something on and in between the LR bracket and bumper that held moisture and caused some localized rust...

The bracket is quite pitted and has some performation..in that area...

I may just paint and re-assemnble for now......but this car deserves better parts.

P/N for the left bracket is 5775269..(CDN parts catalog)...I'll bet the US bracket is different...will check my US parts book....when I find it...