Underground Comix are known for using different prices, covers (art or color variations) and interior content to distinguish between printings.
1st print 1971 has 0.50 USD cover price with 36 pages. Has Peanut Juice brand.
2nd print 1972 has 0.50 USD cover price with 28 pages and different cover. Has AA (Adam's Apple) brand.
Inside front cover with indicia information at bottom of page.