Engine braking UPHILL?
If it has a full Lexus SH, can I assume that the recall would have been done by them, if necessary?
No, just downhill, you don't use a brake going uphill - it is a very useful feature and considerably increases brake pad life. The cars involved were recalled but you should check that the one you intend to buy was actually done (if relevant), some owners may just have failed to present their car for the work.