It looks like the installer found a way to save 2-4" elbows eliminating the swing joints at the same time. No doubt he replaced with what was there by reading the rating plate on the old one. If he had measured the rads he would have seen there is only 1307sqft of installed radiation in the house and a boiler that puts out 1938sqft is just a little oversized. The center pipe on the 6" X 2" tee must have looked good to drain the collision with a combined use of an equalizing line. Other than the Hartford connection, is there something I missed?