This was covered before.

It is my opinion this was done by a rebuilder not by ECO.

Reasons:
1. Why would ECO have two different ways to attach the chrome.
2. Why would ECO drill holes in some very nice looking chrome and put some stupid screws in them. It is like attaching chrome to your 1957 chevy with screws.
3. I have a great deal of ECO parts manuals, and nowhere does it state they offered chrome with holes in them, nor does any of their advertisement show this type of chrome.

The reason the rebuilder did this was to make it easier to replace the glass should it break.

Jack Sim

Author, 1st & 2nd editions of Gas Pump ID book, 3rd edition is now available at www.gaspumpbible.com
Air Meter ID book also available