I've used coloured Sharpies to help disguise lines like that. Mask off either side of the line and then apply the Sharpie. or you could try mixing up some artist acrylic paint colours to get a close match and paint that on with a brush

As the glue line is between the two pieces of veneer, I don't think that you could have done much about it. Acetone or Goof Off may have removed the glue, but you'd almost certainly have been left with a hollow where the line had been which would still need dealing with.

If you can get hold of an amber lacquer spray, then I'd use that on the top after the Sharpie/paint as it will help disguise the line even further. I had a slight glue line on the join on my ES-1, so a couple of coats of heritage cherry red lacquer went on to help cover that up over some Sharpie and you wouldn't notice it now unless you looked very hard.

I don't know what finish you were planning to put on. Tru-Oil is slightly amber, and will darken a bit as it ages, but not quite amber enough to have the same level of effect as an amber tint lacquer will.