the better of the two. The 'original' Tesoro Conquistador was in the 'micro' housing but wasn't labeled as a [size=small]micro[/size]MAX. The early production Conquistador had the Frequency Shift made with a long toggle mounted under the control housing ahead of the hand-grip. It had some design glitches, like the Sidewinder µMAX, and a few other models, where adjusting the Discriminate control made a very pronounced shift in the Ground Balance setting. The shift to be too negative and cause falsing, or too positive and result in the loss from detection of higher-conductive targets like big US dollars, and even half-dollars or at times even a quarter.
The Conquistador µMAX that you have is the improved version that corrected that design glitch. The Conquistador µMAX would be the modern equivalent of the former Silver Sabre µMAX. just like the Eldorado cousin of your model was the 'replacement' for the Bandido II µMAX in the manually GB'ed series. You have cleaned your unit up well and it doesn't appear scratched and abused, so I would say it would depend on the current market trend for used Tesoro's, but I'd go no lower that $150, expect you to get ± $200, and if it performs well someone could take the gamble and go up to possibly $250 for it.
Naturally the consumer would like to pay on the lower end while you, the seller, would welcome the higher dollar figure.
Monte