Where I hunt in IL, that would be right ont he border of pre-rut/rut, everything I've read about decoys is a buck works year round, a doe only works in the rut, even better a doe and a buck during the rut! I'd say if anythign get a buck decoy and use it that time of year, most guys ive talked to would consider that time of year pre rut, go with a buck is my 2 cents.

PS- I'd say full size, 3d style decoy, I've used a 2d style, and look sgreat from the side, but head one its like 2" wide. I think some deer have been spooked by it, I'd suggest a 4 legged 3D style, and any movement you can add to a decoy I'm all for. bobbin head.....add a rag/tail to blow in the wind, maybe with some scent on it.....doe estrus, or just doe urine that time of year.