Bench to Bucket Conversion Advice

I have a '67 Barracuda Fastback 383 S 4-speed with a bench. I am considering swapping the bench with a couple of buckets I took on trade. I think they are factory A body buckets out of a '69, but I am not 100% positive - let's assume they are for the sake of this discussion. I did some searching of older threads that talk about the dimples that should be in the floor pan for the buckets (I haven't pulled the carpet yet) and saw mention of reinforcing the floor for buckets.

My first question is, if these are in fact factory A body buckets, do I need to reinforce the floor if I drill in the factory mounting locations? There seemed to be differing information about the need for this in the threads I saw that seemed to indicate the reinforcement was needed only for aftermarket seats that did not bolt into the factory locations. Would some sturdy washers be sufficient?

Also wondering about whether or not I will need to add any spacers to level the seats or if they should just be a drill and bolt-in fit. Any other tips, tricks or pitfalls anyone has to share?

Thanks