Very much so! Apparently, 'LRX' was the first 'proper' works 1800, and won the 1967 Danube Rally with Tony Fall- Brian Culcheth also used it on an Alpine Rally.
http://www.bluestreaksix.com/Austin1...anuberally.jpg
As you said, an obvious 'works' reg number- in the same 'LRX82_E' series as a couple of the 1967 season works Minis...
http://www.theitalianjob.com/worksminis_LRX827E.htm