Others more experienced can chime in, but I'll add my 2 cents worth.
If you can’t find someone that sells a specific recone kit, you would have to dissect it, measure the voice coil gap to see what size coil you can fit, then browse
ebay and such for a coil that will fit the build. AB says it uses a 3” coil. Not all 3” coils are the same, nor will they all fit, so this takes some precise measuring and finding one that will work. Then of course look for cones, spiders (dual spider???), tinsel leads, dust cap, proper glue, etc.
Ebay is a place to find most of this (also google for recone kits / subwoofer parts). A DIY recone will not be like the original parts, but if you can't get original you have to use what you can get.
Custom recone is not rocket science, but it requires some calipers at the very least for measuring the coil, and research on your part to find aftermarket parts that will work (if no one else can say exactly what you need), also takes some time to do properly, you can’t rush through a recone.
If it isn’t a high value sub, and I don’t mean anything bad by that, but my point is to add up the total parts cost before ordering anything to determine if it is more economical to just by a new one that comes with a warranty. It is a fair amount of work to recone the sub, and if you mess up the first time or two, you could have just bought a new one.