I can’t find traditional bock in the new guidelines but its 5B under the 2008 guidelines. I think bock was stronger and darker than the regular lager beers at the time and for a traditional German bock I’d think you want a starting gravity in the 1.060s. American versions may have been different.
The question to me is the source of the recipe. There were German bocks but as bocks became popular in America many American breweries made “bocks” with regular grains and adding color, not like the German versions which were probably made with munich malt. We see “carmel malt” and sugar in this recipe, both of which I believe would not have been found in a traditional German bock recipe. So this seems like an Americanized version to me.
Bock seemed to have had a bad reputation when I was growing up. As a kid, I heard people say things more than once like “thats the stuff they scrape out of the bottom of the barrel.” Or maybe people I knew were just not educated beer drinkers.