I am officially looking for more correct 14x7" (5x4-3/4" bolt pattern) 'plain' steel wheels for my car.

The correct code wheel for my car is 'CL';

As I have come to understand it, the 'CL wheel was manufactured for/during three model years; 1970-1972.
I have understood that the wheels can be found on, but not limited to: Firebirds, Camaros, Grand Prix.

I currently have a full set (of five) 14x7" steel wheels, and as luck would have it, one is a 'CL' wheel which decodes as being manufactured on March 13, 1970.

I will consider 1971 or 1972 dated 'CL' wheels, if the price is right;
Ideally I'd love to end up with a full set of 1970 dated wheels;
Better yet, I'd love it if the wheels all predated my car's build date of June (first week of June).

I use the term "casually" to convey that I am absolutely not looking to waste anyone's time, but I am also not hell-bent on finding these, and if the asking price for a wheel seems to me to be more than I am comfortable paying, I will respectfully pass.

For those not experience with decoding wheels (this took me a while to figure out myself) the stamp is by the valve stem and should read as follows: 

K10_3_/\_13_CL

_ = space
/\ = valve stem

I have been told that this decodes as:

This decodes as:
K (Kelsey-Hays)
1 (plant location)
0 (year)
3 (month)
/\ valve stem
13 (day)
CL (application code)

I recently found this great site for wheel information:  http://www.wallaceracing.com/rally-wheel-date-code.htm

In the interest in helping members here know what they are looking at (assuming they have 14x7" steel wheels to look at), I believe the following information to be true:
XF = 1969
IF = 1969-1970
CL = 1970.5 through 1972
EM = 1973 & 1974
UC = 1975 through to possibly 1978 or 1979

XF was (used on 1969 model year F-bodies) replaced, or superseded by IF
CL was (used on 2nd gen F-bodies and was) replaced, or superseded by EM
EM was (used on 2nd gen F-bodies and was) replaced, or superseded by UC

I have also run across these two wheels codes being reported as GM 5 on 4-3/4" 14x7" steel wheels, but I do not know their application: XG & XT

My current set of 14x7" steel wheels is (as alluded to earlier) mismatched;
In that set I have two different offsets (my measurements are from bolting surface to outside lip of wheel); 

IF 4-3/8"
CL 4-1/4"
EM 4-3/8"
UC 4-1/4"
TB 4-1/4" (not an F-body application wheel; probably from a safari van)

Thanks in advance for reading this, and hopefully humoring me :)

Jonathan
Calgary, AB