[Hammarlund] questions about the HQ-170

[yash at aol.com]

     Been looking at some pictures of the HQ-170. Have some questions to ask.
1. there is only one model of the HQ-170? what is a HQ-170A?
2. Where is the SN# on the radio,mine has no rear sticker, stamped some where?
3. I saw several pictures that were listed as a 170 and the cabinet had a lift up door on the top, like a Collins. were there different cabinets during production? my cabinet is solid one piece, perforated metal. 
any info would be appreciated. 73
dale wt4t