Prior to adopting A.M.O. standards, Ben Pearson used the 'X' to denote 2 pound increments in bow weight. If the X is placed before the poundage it was minus 2 lbs from the marked weight, X40 = 38#, when placed after the poundage it meant plus 2 lbs, 40X = 42#. Your bow marked 40XX is actually 44 lbs. This all changed when the A.M.O. standards were adopted.
Easton still makes 2117's. If sticking with aluminum, I'd personally lean towards 1916's or 2016's depending on your draw length and desired point weight.