Yes you should have primed with a etching primer first, but some primer surfacers can be used as both etching and surfacing...even though there is always a seperate one recommended by most paint comps....It comes down to how good of a primer you used...if it was like ppg's k-36...you prob will not see any problems...if you used the cheap stuff and it has been sitting for a while...that stuff is very porse and will let the humidity oxidize your steel through the primer..and could cause some adhesion problems in the future....Most people will tell you the way to go is a etching primer first, surfacer next, then a siller and then the top coats...All of these have a window to put them on after each other unless you sand before your next step...I would say it is for sure a gamble..sorry...hope this helps