Found some 1999 dated Kodak Ektapress 1600 in fridge so had a go using my 1975 KX -- I rated it at 125ASA same as I found the Old Fuji Press 1600 film. Processed in used C41 for 3 mins 45 secs BUT still 'Thin' negs -- maybe developer is on its way out.
Available Light in Brentwood Sports World with SMC Pentax-M 50mm f1.4
JW's in Brentwood HIgh Street at f2.8 on SMC Pentax-M 50mm f1.4
SMC Pentax-A 24mm f2.8