You're obviously a "night owl." I intended to address the ID's or crests. Like shoulder patches, unit crests were first authorized in 1918 but didn't come into general use until the mid-1920's. A lot of the earlier ones were designed by members or former members, enlisted or commissioned, of the units represented. In recent years, this function's been taken over by the Institute of Heraldy.
There's a lot of symbolism. The dragon in the gate on the 14th Infantry crest, for example, commemorates the regiment's participation in the Boxer Rebellion of 1900, particularly the Battle of Tientsin.
All crests up to the 1970's or so were either brass or sterling silver. Brass could be polished to a higher luster. The ID's you have for the 610th and 893d TD's are probably Sterling. If so, it'll be noted on the reverse of each. A lot of these disappeared when silver prices went crazy in the early 70's. Another example of history gone forever.
Also re the 610th and 893d crests, the blue (azure) is the color for Infantry, a reminder that TD's, although later a separate arm of service, originated as infantry units (893d was originally constituted as 93d Infantry Battalion [Antitank]).
Uncle's been cutting back a good deal on toll-free numbers. Contact the library, but, if you can't get a toll-free number. I might be able to call collect.