I believe that the peak is Cerro de las Polleras.
See also here:
Photo of Cerro de las Polleras
Yes, you are absolutely right - if you look on the Plata Traverse page I have just revised (linked to this photo) you will find a photo that confirms I finally got it right in the summit views section - and also (I think) correctly identified El Plomo and Juncal - what do you think?
Thank-you Sir - you are close... if you see above Scott has got it right - it is Polleras. I think El Plomo is the next peak along on the western horizon - and actually shows up on another image I have linked to Plata Traverse page I have just revised (that you kindly voted on - thanks again!)