If it’s a multiplier farm especially gilt, that’d be a little different, and lagoon construction will make a difference as well.

most typically lagoons are relatively shallow with a large surface area, so obviously rainfall has a large bearing on the dilution of the lagoon contents, in addition it’s kinda hard to get a large lagoon stirred up very well, so the first stuff to come off is usually mostly all water, with most of the nutrients sitting at the bottom.

occasionally though there are a few examples of deep lagoons that the above doesn’t really apply, not quite as good as deep pit manure, but better than shallow lagoon.

i’d do alittle more investigation and see what kinda equipment they are using/gonna use.  If they are gonna use a couple of stirring pumps along with the sprinkler pump, it'd probably be worth the hassle, but if they are just gonna drop the sprinkler pump in and see what they can pump out, then I’d probably shy away from them doing it this spring.