I picked this piece up from a flea market the other day for 6 dollars. It was supper crusted and appeared that it might have a small crack in the side. After a good (first) cleaning, No Crack! There are no markings on the bottom except for a dimple in the middle. It says AB&I on the little helper handle in the front. It has no heat ring. How old is this piece? Is it collectible? How much is it worth? Thank you in advance for any info you can provide!