Help Identifying Aftermarket Shocks

I just bought this 2003 a week ago. Got it jacked up for a brake job and a shock swap when I realized that every shock replacement video or guide I find online shows the shocks and the springs as separate. In fact, the shocks I bought to replace these do not look like I'll be able to get those little brass spring restrictors around it.

Am I going to need a specific Bilstein shock to replace these? I can't find anything that look like these, with the little threaded bit. Any help identifying these would be greatly appreciated.

So, after taking the shock out, it looks to be a normal bilstein shock with a coil over kit. My only issue now is that the shock seems to have a groove cut in it to accommodate a clip that keeps the coil over sleeve in place. Stock bilstein shocks don't seem to have this groove. Is this something that was machined in?