I thought I had some pics but I can't find them now. I had a local shop powder coat and weld the gussets on since I haven't welded since I left the farm.
It's been several years ago but as I recall they had to unbolt the trailing arms from the front brackets then weld on the gussets and then reinstall the trailing arms. The gussets are just some added steel and angle iron to reinforce the current mounting brackets. This supposedly affect pre-#200 build cars but mine needed them. It could be a big safety issue especially if you are running much HP which could stress the brackets and crack or break them.
You could take a picture of the brackets and send to Cashburn (a very helpful BDR dealer that posts to this forum) and see if it looks like it has already been added. You could also contact BDR in FL to see if they still have the gussets available. It shouldn't be too much $ to install. I probably paid $100-150, just don't recall for sure.
I don't have the car here, I keep it in storage. If I get it out this weekend I'll take some pics and post. Good luck.