a great site for first gen firebird is
www.firstgenfirebird.org
they have a vin and body tag decoder. I entered your body tag info and came up with this:
1967 Pontiac Firebird Convertible with Custom Trim Option
The paint was Verdoro Green with Black convertible top.
The trim color and material were Black Custom Option Vinyl
This car has the Fisher Body Unit Number 9,181 built in the 1st week of March at the Lordstown, Ohio plant.
Five Group Accessory Codes ( wd 2elgr 3m ):
1st Group (digit not shown)
D .... Power Convertible Top
W .... Soft-ray Tinted Glass (Windshield Only)
2nd Group
E .... Air Conditioning, diff ducting (Firebird, GTO)
G .... Console
L .... 4-spd Manual Transmission Floor Shift
R .... Rear Seat Speaker
3rd Group
M .... 326 HO Option (Firebird)
4th Group
No Accessories in this Group (or No Codes Entered)
5th Group
No Accessories in this Group (or No Codes Entered)
They also have a vin breakdown.
Results for: 223677U161301
1967 Pontiac Firebird V8 Convertible
This car was the 61,301 made at the Lordstown, Ohio plant.
If it was a 400 car, it'd have a "3f" instead of "3m". Unfortunately, 1968 birds didn't have this info on the body tag- requiring you to purchase the pontiac historical services info for sure.
The "1" in the vin tells you it's a V8. 6 cylinder cars had a "6". this is the first # in the production sequence. (161301)