In searching my photo files, the tank on 09410 appears to be a k-27 tank that has been cut off at the lower row of rivits for which held the bottom plate of the coal bunker, and the old tank bottom welded and rivited on at the point of the cut. That means that the water leg of the tender only goes around the coal bunker, not underneath. AT the same time as that was done, there were extensions added to the top of the coal bunker for added capacity.
If you make the assumption that the conversion was done from a K-27 tender, and you rule out all of those that either exist todad or were sold or wrecked, and you further rule out those that had patches that were welded on the firemans side, up into the coal bunker area, you end up with only the 456 and the 461, assuming the conversion was made in the 1950's. If the work was done before 1950, both the 450 and 451 would qualify.