With Patek Philippe Extract from the Archives confirming production of the present watch in 1959 and its subsequent sale on September 25th, 1969. Further accompanied by a Patek Philippe Certificate of Orgin dated September 1969 and photocopies of the original sales invoice which further reflects the purchase price of Sfr.6,970
Produced between 1952 and 1963, the reference 2438/1 was the first water-resistant-type perpetual calendar wristwatch with center seconds made in series by any company. This wristwatch was manufactured in conjunction with the reference 2497, its counterpart with a snap on back, first introduced to the market in 1951. Between the two references, a combined total of only 179 pieces were ever created. This famed wristwatch was cased in Geneva by Wenger, one of Patek Philippe's premier case makers. While the reference 2438/1 is clearly differentiated from the reference 2497 by its water-resistant screw-back versus a snap on back, it also features a slightly smaller case, 37mm as opposed to 37.8mm.
A similar model is illustrated in Patek Philippe Wristwatches, by O. Patrizzi, Volume 2, p. 144, pl. 615.