Not from the factory but it wouldn't hurt to apply some also use some weld through primer.

When you fold over the rear edge of the A panel be careful not to dent it I use paint stirrers or something similar so the tools are not crimping down on bare metal, you may need to put some small cuts in it by the upper radius so the metal has enough room to spread.

thanks Mal.  Is there seam filler on the long inner side of the panel? 

It is welded down the wing / A panel seam then tack welded at the top and bottom onto the sill.
The rest from the top to the bottom next to the door edge is folded over with no welds.
The  door needs to be removed (heat up the securing nuts as they break off usually) and take note of any shims on the door hinges but test and re fit the door before you weld up the A panel so you get the gap correct.

I've got a MK 3 or later which needs the A panel replaced or repaired.  How does the panel weld up to the inner panel at the door hinge panel?

It's mostly the lower 6-8" that's rotted out and bondo'd over.  The car is very straight and little rust, so I"m tempted to patch from a stock replacement panel.

Does this panel get welded vertically along that inner line? to the Inner A panel?  Not sure what compromises the sheet metal above and below the internal hinges.