Studs for mounting steering box

The steering box on my 66 barracuda finally gave up the ghost and started puking oil out the sector shaft. I've owned the car since the late 80's and I've never replaced the box.

Last weekend I decided to pull and swap it for a spare I had. I found nuts holding it in place instead of the the typical twelve point bolts. Anyone ever seen this done before? Possibly done by dealer? Should I put bolts back in instead of the studs?

The box was held tight to the mount and all the internal nuts were solid. Just not sure I should go back with them. Could there be strength issue?

Unfortunately, my spare was miss marked and ended up being a b-body box. I got one on order from Steer and Gear. I didn't have a lot of confidence in the local steering repair shop when called them.