[Arran]

Here is another thought or two, the service info mentions that the diagram is also for a 37-620 as well as a 37-630, the latter has the shadow meter, the prior does not. Maybe the 37-620s needed those caps because of the lack of a shadow meter but the 37-630 needed them? It might be educational to compare this example to other chassis out of this series, I think it was earlier this month that someone had a 38-7 (I think) with a few mystery parts that were left out of later production sets, including an odd looking RF choke, I thought it was a bodge but someone found a thread on the ARF with the same parts.
Philco was usually good about documenting revisions, though they sometimes have errors in the diagram that were missed, showing wires connected together where there wasn't, or at least not clearly defining them as NOT being connected. There have been exceptions with not denoting changes, especially on earlier models.
Regards
Arran