Dear Don,

in 1988 I saw a chip with mfg. date of 1980. Of course I can't guarantee that it can give an idea.

But don't think that 8051 micros are old style, since there are always new versions of original 8051. Today Intel, Philips, Siemens, Dallas, Atmel, AMD, OKI, Harris, Hyundai and other companies produce more than 100 derivatives of 8051. It's an industry standart.

Best regards
Selim Dilmac