Motorcycle Repair: Spark plugs/caps, 1971 honda cb350, clymer honda

Question
Hi,
I am trying to figure out a spark plug problem on my 1971 Honda CB350.
Problem 1: according to the serial number on the engine it is from a CB350G(1973), while the frame is indeed a 71.

According to my Clymer manual and original honda shop manual (as well as the NGK parts website) the spark plug to use is the B-8ES (or the BR-8ES)-(actually its the same plug for both the 71 and 73 so I am guessing the fella who rebuilt it made an error).

I went to change out the plugs today and noticed that I am currently running a B-7ES.  Now, the terminal of this plug is threaded, unlike the much thicker covered terminal of the new plugs (BR-8ES).
I have also noted that the side electrode is longer (and thus deeper into the cylinder).

I am unfortunately unable to replace the current plugs with the (proper) replacement ones until I have figured out the following:

My questions:1. Is the BR-8ES actually the proper plug?
2. Have I done any damage by running these plugs)?
3. Is it simply a matter of putting on the proper sized spark plug cap, or am I faced with rewiring the whole unit?   
Thanks a ton,
Dave

Answer
Hi Dave...

If Clymer, Honda and NGK all say the proper plug is the B8ES, then that is the plug to use. The B8ES is a "cooler" plug than the B7ES, which is a hotter running plug. I doubt any damage has been done by running the B7ES plugs. Best way to know is to look at the plug and compare it's appearance to the chart found in the Clymer manual. There are certain times and conditions when running a hotter (B7ES) plug is desirable. Now as for the spark plug cap... that's an easy one. The new B7ES and B8ES plugs have a removeable adapter on the top of them. You can remove that adapter by CAREFULLY unscrewing it with a pair of pliers. Then your caps will fit on the plug. I say to remove it carefully cuz we have had a few boxes of those plugs come from NGK and that little adapter was screwed on way too tight, and when I tried to remove it, the inner shaft started to come out. Don't squeeze the pliers any harder than is necessary. Hope this helps you Dave... let me know if ya got any more questions!!

Jack