Well Marked English Hammered Pewter Pitcher: Help, Please!

~6" high to finial, 4" diameter base, 3 1/4" rim; weight 20.75 oz.

Many fine details reflect a high quality piece: the hollow, vented grip with seam, the 5-barrel hinge without even a hint of looseness, the lid that fits snugly in the shallow rim recess, the lack of discernible seam in the body, the way the bottom is inserted (see the corners of pic 6), the highly polished underside of the lid which must have also been the case with the rest of the interior, the presence of two maker's marks, plus no less that 3 alpha-numeric production codes along with them...

This beauty isn't young, and has been used...but there's zero evidence of blemishing dents, dings, scratches & etc to mar this vessel. The outer surface shows color and/or soil but I'm loath, in view of the otherwise near-pristine condition, to approach that patina with any cleaning regime at all.

My dang problem is that in spite of two well-defined marks, including the nation of origin...I have been unable to locate any reference at all to information about the maker. I throw myself upon your many-faceted expertise an' experience, hoping to learn any specifics about National Products, the era of manufacture...an' what the word 'silverod' means.
As always, thanks for lookin'!

 

It made me curious as to what silveroid is and from what I found, it's not really pewter but a different alloy if this is correct.

https://www.treasurenet.com/threads/very-old-flower-decorated-spoon.23074/#post-216982

An alloy was developed specifically to meet the needs of the American pocket watch case that answer the question of durably and affordability. This combination of 45% nickel, 54% copper and 1% manganese was called silveroid, silverore, silverode or silverine. It was easy to polish, very hard and looked just like coin silver.

 

This one has a clearer mark showing the missing "i".

https://www.ebay.com/itm/2957237974...jwxjMgpTEi&var=&widget_ver=artemis&media=MORE

 

Yes! I noted the gap where the I should be, but didn't make the connection to a missing letter...Thank you!

 

The things a fella learns in his dotage...an excellent reference sis, an' I'm grateful to you for it!