What year box do I have?

Hello there everyone. I have been lurking here for a while now and I have gained so much valuable information. I just wanted to say Thank You for all the help I have received even if you didn't know you were helping.

Now for the ask. I have a 1984 K10 long box that I purchased several months ago. The box has been replaced at some point because it now has the round filler hole on both sides. The passenger side of the box is caved in badly beneath the filler neck all the way to the front of the wheel well. The front of the box is also bowed toward the cab where I assume something heavy slid forward and crashed into it. I should also mention that it has the original 1984 tailgate.

How do I identify what year box I have? I know it is a 70's model box but I have no idea what year. When I looked at panels on LMC Truck it says there are two versions. Version 1 is 73 -76. Version 2 is 76 -78. I watched some Youtube videos of replacing the bedside panels but really wasn't able to find anything that helped me identify the year of the box. The one thing I know is that my current box has 5 bolts per side connecting the front and side panels. The videos I watched had 4 bolts per side. I would appreciate any help you could give me.

Thank You.

My '74 has round, (exposed gas caps) filler holes.

From what I understand the round hole went to 78. Do you recall how many bolts are holding the front to the side of your box?

From AMD's website on the 73-76 and 76-78 bedsides fitment.

Thanks legopnuematic. That's what LMC's website says as well. But my tailgate is original to the 84. (It matches the cab and front end). It has the post. The box is a completely different color so I know it's been swapped. I tried to search online for the 5 bolt pattern on the front of the box but couldn't find anything. The front bed panel says it fits 73 -87 so maybe it doesn't matter what the bolt pattern is.
That leads to the question of whether the only issue is that the hardware for the tailgate latches is different or mounts differently. If so, maybe the hardware could be swapped.

The bed of my '74 has 5 bolts vertically holding the side to front panels. There are 2 fairly close together at the top next to the stake pocket.