The LDA slides are missing the disconnector cut.
One could be milled in the LDA slides
not my info;
Actually, it's probably fairly easy to put an LDA slide on an SA frame, but a machinist's nightmare to go the other way.
And the LDA frame is quite different, too, in the areas where all the naughty bits go.
Short answer is that you really can't turn an LDA into an SA without being a serious machinist, IMHO....
(The LDA slide really only lacks the little dished opening for the disconnector. The rest of the differences shouldn't matter too much. Worst case is you'd have to kill the Series 80-style drop safety, but that'll cost you $6-ish from Brownells. Unfortunately, the frame is set up quite a bit differently - no place machined for the trigger bars, for example, and the lockwork seems to require some interesting changes in the frame, too.)