Singer HVAC dates?

Can anyone help me out with dates these units were built?
Singer furnace model #G82104 12B NAT, serial #0210473-C02-0257.
Singer A/C unit model ACR50124-25 F, serial #0113950-D21-0325.

Thanks Jon

Jon, I cant find the furnace model at all but the AC appears to be a 1978



This is a long shot, but read the first few pages then scroll down to page #30

There is also a list of phone #s that may have the info you are looking for.

Good luck.

According to my information, Singer were sold by Remington Indusco Inc. and were common in commercial applications. There does not appear to be any consistency between manufacture date and the various numbers.