I think it may be possible but I usually just use a very fine brush and touch it with stain. I keep some alcohol based stains that I mix very thin for this sort of touch up. I've never thought about what you suggested. I don't know how much of the yellowing is actually the wood and how much is the finish. The wood will oxidize naturally with exposure to the sun and air but most of the finishes we use yellow too.
I would be tempted to just leave it and let nature take it's course but since it belongs to someone else I would probably add just a bit of tint to get it a little closer to the rest of the top. You might wipe down the area with naphtha or alcohol to get a feel for the finished colors.
When I tint a repair, I don't try to get the depth of color I need in one application. I like to keep the stain light and thin and work my way up to the color I want. The alcohol dries so quickly that it doesn't take much time. I prefer to leave it a bit lighter than the surrounding wood and I like to check it in direct sunlight to get a better feel for how well it actually blends. In the end, leaving it a bit light is better, time will blend it all together.