Looking at the dedication plaque on the Salt Lake Temple, I was moved to wonder: What's the deal with this stereotypically "American Old West" style of lettering, where almost every letter has sort of "serifs" sticking out of the middle of each stroke?

Is there an accepted name for these seriffy-looking things?

What is the history of this style of lettering? Was it actually common in the Old West? Do the little seriffy things skeuomorphically imitate some inherent quirk of old wood-block type, or have they always been purely decorative?

About the style,

Tuscan Fonts

Tuscans can be described as decorative display faces with characteristics that usually include one or more of the following: bi- or trifurcated (branched) serifs or mannered stroke terminations (pointed, rounded, concaved, chiseled, wedged…); an active, energetic contour; and medial decoration. Tuscans can also be additively ornamented (shades, shadows, fills, patterned interiors…).

The whole history at the Hamilton Wood Type & Printing Museum

The origin dates from the nineteenth century when the typography leaves the printed paper to move to large posters with giant letters made in wood types simulating the store signs. The short reading allows more attention to the ornamented strokes than readability, therefore, the most ornate were the most popular.

Source typekit.com

There are more examples in this answer

Spurs

A small projection off of a main stroke.

See #15 here.

Although most explanations will use an uppercase G to show a sample, they are still spurs when protruding from a primary stroke of any glyph.