I've no reason to doubt the 1921 yardages, or that Watson originally designed the course. I haven't seen the LA Times article but there are a number of articles from San Diego papers indicating that Watson designed the course in 1920 and it opened in 1921. The same yardages are listed, give or take a few yards.
Bell was brought in to modernize the course in or around 1929, but it was not a complete revision, and although the bunkers were modernized and three or four new greens built, most aspects of the original Watson layout remained. I don't have the articles in a form to post or send right now, but here is a bit of a summary from my notes taken while reading the articles.
Summer 1920. Land in Chula Vista secured and Watson hired to make a survey and lay out the course. (Land was actually leased from a development company but it may be that the club or aspects of the club controlled the development company.)
1920 - 1921. Progress reports on the course very favorable. Watson touted as architect top architect responsible for many top courses (aside: courses include White Bear Yacht Club)
Sept. 3-5 1921. All grass Watson course opens with three days of tournament festivities.
Summer 1924. Overzealous chair of green committee and professional play Pebble and other Monterey courses and decide they know enough to tinker with Watson's work [my editorializing here obviously.] Build some new tee boxes, plant trees between holes to make course harder and prettier [and to block those pesky views of the ocean] Tee on 17th moved, bunkers added to limit golfer's options.
Circa 1924ish - Nines swapped and swapped back, maybe a few times. Reference to Watson having been architect.
pre-summer 1927. Possibly other unspecified tinkering.
Summer 1929. Bell directing "modernization" work at Chula Vista. Not a redo or a complete revision. Reportedly one new hole, three new greens, general re-trapping to replace old deep pits with bunkers which drain better. Major changes a new short hole fit between 11 and twelve. Scrap short 16th hole. New green for 2nd 15 yards longer and to the left. Lower 9th green. New tee on 17 and new 17th green. Maybe new green on first hole (to left of old green) as well. Course now 6615.
I looked at the SDCC website, and I see they credit Bell with the original design. An understandable error I am sure, but this is not accurate, I don't think. So many contemporaneous reports indicate that it was Watson, and that Watson was involved throughout construction. I guess it is possible that Bell was working for Watson during the construction, but there is no mention of him in any reports I have seen, and the reports leave no doubt that it was proudly a Watson course.
As you know Bell was quite active in San Diego and environs more toward the end of the 1920's, and he certainly became the more-hyped designer in the late 1920 and into the 1930s. This was especially so in San Diego because of his involvement in the large Mexico project, and so many other prominent projects in the region. At some point perhaps the club decided they would rather be associated with Bell than Watson, or more likely they just lost track and since everything else in the area had Bell's name on it, and since they knew Bell had been there, they started to consider it a Bell course.
When it comes to credit where credit is due, I would be surprised if there is any old dead designer who has gotten the proverbial golf course shaft as often as Watson. Bell is under appreciated today considering his body of work, but he is a cult legend in comparison to Watson.
Hope this helps, I'll get you some articles when I have time.