Japan pressings catalog numbering details
From Adam at Genesis Museum:
I found out some interesting info on the Japanese LPs. For a while I thought they were a certain series, SFX meant double LP, or that they necessarily went in sequence. Here's what someone told me:

RJ-5xxx is a price code for 2200 yen
RJ-7xxx is a price code for 2500 yen
SFX-xxxx is a price code for 4000 yen

So for example, the first Japanese lamb was two LPs each labeled RJ-5 so the cost was 4400 yen while most double LPs were SFX. The first Japanese Trespass was expensive for a single lp, but at least explains why it had the SFX code. It was for pricing reasons and not attached to release date, quantity of LPs, etc. It must have been some sort of special release though for it to be priced so high.