[Hallicrafters] HT-4, BC610 Question

[Ed]

I was recently in conversation with my friend John who operated a BC-610 all 
through WWII and occasionally after the war at a club station, he had never 
seen an HT-4 version. I've never seen one either, how many HT-4's were made 
and what was the years of their production run? John seems to think the 
BC-610's were more powerful, was it that or were they just made more rugged 
for the war work?
73,
Ed-KV5I