That may be less-incentivized to haggle on one you order vs. one on the lot, but you can order one without ALL the options, vs. what's mostly on the lot, so you'll probably save some money there. This hour's tariff status is unknown, and how it will change is a complete unknown, so if you want/need a new vehicle now-ish, find inventory or order it now. Otherwise, wait until all the silliness settles down. IF tariffs affected pricing, though, the afterward may be kind of problematic as I wouldn't see prices coming down much and for a while.
When we ordered our 1500 AT4 in February, we signed the order form. The sales guy said that locks us in on the price and rate. I have no clue at this time whether or not any added 'taxes' will be applied when we show up to purchase it, but I'll be standing behind the signed order form if that's the case. It works both ways.
We should know in a few days. The truck is being shipped to the dealership as I type.