Now this is esoterica Gene!!! and actually, I think spurs are very much part of the study of arms and armor, as from medieval times they were actually a sign of rank. As for tenuous, not at all

with the great tie in with this classic movie!! probably more for the actors than the actual content.
The spur didnt really kill the guy with a spur (so we wont need to worry about activists seeking to outlaw spurs now

but actually threw it at him, presenting the distraction needed for the deadly gunshot.
This example looks to me markedly Mexican, though I cannot claim any knowledge or even awareness toward this topic. As noted by Chris, the presence of spurs is well seated in American cowboy tradition, which has of course borne its origins in the colorful history of New Spain. This heritage in turn carries the traditions from medieval times and chivalry brought from the Iberian Peninsula.
I think that the distinct appearance and elaborate decoration may be more of a Spanish influence, more than regional application. While the huge rowel signifies the 'espeula grande' type , it seems more likely Spanish Southwest or Mexico, though certainly the gaucho examples are well noted.
The use of stars in linear motif would not signify American association in my opinion though, as these stars are known to be used in many types of insignia, flags and regalia. As spurs were often custom made, there seem to be any number of possibilities.
It is very true that the styles and flamboyance of Mexico in the material culture of its frontier and Spanish Colonial history is one of the very things that make the study of these arms and accoutrements so exciting in my opinion. The Mexican vaquero was stylish indeed, as were the Mexican cowboys who carried the traditions forward.
Returning to the movie images noted by Gene, who can forget the rugged and elaborately distinct character and flamboyantly festooned bandidos and revolutionaries in western movies with huge sombreros, bandoleers, flared pants and clanking rowel spurs. While some might see them as cartooned cliche's, I see beyond that and see the spirited and rugged caballeros who formed the character of not only Mexico, but very much America itself.
It would be great to learn more on spurs and thier history, and think it is an excellent topic to pursue further! Outstanding Gene, thank you!!
Alan, good one there from OZ, love the kangaroo kuddlers!!!
Chris, excellent note on the frequency of seeing spurs around, and I can formly attest to that as the 'bookmobile' courses through the Southwest constantly.
All the best,
Jim