Are there any stub ups from the footer steel that are tied "continuous"? (lapped 24" in the case of #4)
If so you can usually tie to that but you need a continuous path to the steel placed "near the bottom or vertically, and within that portion of a concrete foundation or footing that is in direct contact with the earth" (250.52(A)(3) I doubt they will accept a cold joint on top of the footer as being in direct contact with earth.
Florida has made the Ufer one of the check offs on the footer inspection to avoid these problems and it has been that way for a couple decades.
If you can't find a piece of footer steel you may be chipping your way down to one or coming up with another acceptable electrode. YMMV on that one.
If these "slab dowels" are J hooks with the typical 12" lap on the bottom tied to footer steel, you might find an AHJ with a good enough sense of humor to let you cadweld or even acorn a #4 to several of them up top and call it a continuous connection. I believe it would meet the intent.
