At 34.38 min. during the sex scene, there is a 1939-40 Philco radio in the background.
Samson mentions that he'll pay the whore "a sawbuck" to see how fast she can make his friend orgasm. When she declines he then offers her ten dollars. A sawbuck is a ten dollar bill.
Clayton 'Jonesy' Jones' limp seems to be more pronounced at times and less noticeable others.