+1
For others the outer edge along the top and sides will have engine color also though difficult to see in the picture. The paint on the bottom section is from painting the oil pan (plate was attached/held to the back side of the engine when it was being painted) while the bare surfaces (not masked on these engines) around the starter attachment point, assure a good ground for its operation
Believe the glue was there hold a gasket (foam in type) that rarely survives after all these years. How much glue and how neat or not so neat depended on the worker
What is interesting is that the glue is not found on all small block engine plate applications or at least not all the way around the crank opening while on other examples we can find remaining evidence of a round gasket around the hole in some sections but not in all (engine paint on the metal surface)
Might there be (haven't checked and compared just thinking about the possibility) is this a manual verses automatic application difference?
68 J code automatic example from my collection. No adhesive wipe but gasket and paint to lower edge
69 302 manual trans example. Paint stops short of lower edge (crank opening) and adhesive wipe