If they were stored properly, your good to go........

I went thru this last year. I added some after run oil to the engine and hand proped it over to see how it felt. Then removed the glow plug and added more after run and purged all of the old storage oil out. I then made sure that all the oil was out by turning them over with the starter. With fresh oil in I connected the fuel and started the engine.

One engine was a little stiff.... I had been breaking it in with a 50/50 mix of castor and syn...after adding the air tool oil and motoring it over with an electric starter it was much looser. And after running it, it was normal again...

Richard