Auction # 2501 ARGENTINA: Special January auction

GJ.1723N, 1976 Figures 5P. with watermark, block of 4 printed on UV neutral unsurfaced paper (also called fiscal paper), MNH, excellent quality. VERY IMPORTANT: the few examples known until now came from a single off-center sheet, I recently found a few examples from another sheet, VERY WELL CENTERED (about 40 stamps only!), extremely rare!