If you can't find one on a lot, dealers are being told by the manufacturers now to expect a 4 to 6 month delivery on ordered units. That estimate will likely get longer in the upcoming weeks. So, it appears a May delivery is about right for one ordered in January.
Unfortunately, manufacturers are experiencing severe shortages of raw materials. Insulation and foam are highly constrained right now, so there's nothing to put in the walls and floors to insulate, nor the padding to make chairs, sofa's and beds. Add in the other items that are backordered now such as air conditioners, appliances, water heaters, furnaces, etc. There are thousands of partially built units just sitting on assembly lines waiting on the raw materials and other backordered parts that're needed to complete the builds.
Oh yeah, then there's the never ending demand for RV's right now. From what I heard from a dealer, Keystone has a job book of over 9,000 units to build that were ordered, just for the Cougar brand alone.
Check back with your dealer for a delivery date periodically. If they come back to you with any dates after May, make sure they will price protect your purchase. This dealer I heard from said manufacturers are hiking up prices across the board by as much as 8% on June 1st. And, if you're purchase agreement with the dealer is not price protected, they'll likely pass the price increase thru to you if they do not ship and deliver by that date.