"In the interest of historical accuracy, I doubt if an "old No. 4 Scoop" is used."
John, that is exactly what was used for decades to fire hand fired coal burning locomotives. Sometimes they were customized by rounding the corners a bit, but the #4 was the most common size.
The reason 492 would have been a good candidate for restoration is that it has a much newer boiler. The 490 series engines are all 1903 Baldwins. 492 has a 1948 boiler barrel, as was pointed out earlier. As I indicated, 497 was restored simply because it had been abandoned in servicable condition in Durango in 1968 and was still in Durango when Bradshaw bought the Silverton Branch from the D&RGW. There wasn't any search made to determine which 490 would be the best one to restore, because he only had one at the time and it was already there.
Now that 497 has been set aside, it may make more sense to consider 492 to be restored because of the far newer boiler barrel.