I looked at my box and the assembly manual and both support front loading. There are Y shaped fold lines on both sides of the box to allow the thicker end (the edge) to pass through the opening.
I believe I bought the box at CARS. Not sure of a vendor.
The tabs they sent are j-nuts and the prongs are not meant to be bent but simply center the nut in the hole and provide a shoulder when the screw is tightened.
OK. Thank you. Will certainly look at that when I try it again. Also would like to add, that I got the interior all back together today. I can't believe how easy it was to put the bucket seat in considering where the studs in the tunnel bracket/track are located. It was tight but I got everything started the first attempt. Not even a single cuss word. Tomorrow, I'll put exactly 5 gallons of gas in the tank and see how the new gas gauge reacts. I read where it's a 20 gallon tank so it should register 1/4 tank. Then Wednesday, it's suppose to be near 70 degrees. I think a cruise is in the air, Carmine.