You have an XBR500SJ, the last model sold in the UK. This is the model with the auto decompressor on the end of the camshaft.
In every other respect it's identical to earlier XBRs, albeit the first models had different front indicator mountings.
In what way are your clip-ins different? I've had GBs and all the models of XBR and the only difference is that the GB clip-ons are slightly lower. Some of the clip-ons appear to be one-piece whereas others look like they are bolted together, but the dimensions are exactly the same. I'm guessing that as with the exhausts (early ones have a separate silencer and downpipe) the changes were made to save manufacturing costs. The items are still interchangeable.
Cheers
GC