I believe it is a 577-R because it matches the original Wayne literature I have. If you look on page 330 of my Gas Pump Identification book you will see (except for the location of the sight glass) it matches the 577 shown on that page.
I might also add, that the Blue Book shows two versions of the 577 (577-R, 577-RC), it could be wither of these, I don't know what the RC looks like.
Author, 1st & 2nd Editions, Gas Pump Identification books
Author, 1st & 2nd Editions, Air Meter Identification books
And, 3rd Edition of the Gas Pump book to be available shortly
Last edited by Jack Sim; Thu Oct 19 2017 08:52 PM.
Author, 1st & 2nd editions of Gas Pump ID book, 3rd edition is now available at www.gaspumpbible.com
Air Meter ID book also available