I find that AKs generally come apart without any problems, so accessing gearbox should be easy enough. I can't say for certain whether that AK has a quick-change spring or not, but I'd guess not. I've not seen an LCT one with quick change before. So you'd have to open up the gearbox, but there are loads of YouTube videos out there showing how to take apart a Version 3. Alternatively, you could take it to a local shop to have a look at.
If you can find an LCT from a UK site that might be better, as they'd probably do it prior to selling it, but I had a quick look now and most appear to be out of stock. unfortunately.