That looks OK to me.
If the frame originally had a tubing sticker, then it should have one now! As long as it fits between the seat lug and the panel, I don't see why it would look "cramped".
I like tubing stickers and a frame made from 531, 753 , Columbus SLX etc without the original tubing stickers doesn't look right to me. I don't even like the Reynolds "renovated" sticker you see on resprayed frames.
It does look a little odd with the Reynolds sticker squeezed in there. But like you say, if that was there originally, it should be there after renovation. The problem is it had been repainted blue before I got my hand son it, so I have no idea where it was originally. If I had seen the original paint it would have made it so much easier.
Here's some low quality pics of the current panel as it stands: