I recently bought this running and driving 73 LeMans. It needs the front seats bolted back down, could anyone point me in the direction of a picture of where on the floor pans they get bolted to?

Nice find and another Mich Pontiac fanatic.  Welcome.  Bench or bucket seats?

Front seats are buckets

Do you have the buckets?   If so,  check the bolt holes in the seat frames.  See where they line up.  If you don't have matching holes, they may not be the correct buckets for the car OR more than likely it was a bench seat car from the factory.

I do have the buckets and ok thank you

To JUSTA's point, bucket seats should have four mounting holes or studs for both the driver seat and passenger seat of the floor. If the studs or holes are not there, then the car may have been built with a bench seat which only have two holes/studs on each side. There are commercial kits available to convert a bench to a bucket seat.

So the first question will be determining what the car originally came with. I had a 73 Lemans Sport Coupe when I was teenager. It had bucket seats. Given that you appear to have a base Lemans (I say that only because I don't see any badges on the car right now), it is possible that your car came with a bench seat from the factory and you are missing holes or studs to mount the bucket seats properly.