Re: New shoes for my 4\" .357
I'm about 99% sure those are Colt factory First Type Target grips with the checkering sanded off.
First, note the position of the Silver medallions.
The medallions are placed just slightly higher and farther forward on First Type grips, and I've never seen a non-Colt copy position them there.
Second, note the slightly rounded edges. This is a classic sign of a sand job.
Here's a pair of original un-sanded First Type grips.
Note the position of the medallion:
Here's a pair of Second Type.
Note how the medallion is moved down and back slightly.
Every Colt grip of this type and later, and all copies I've seen position the medallion here:
What you could do is have someone re-checker the grips with the original type checkering to restore them to original form.
This would be a lot cheaper than trying to find and afford a set of original First Types.
However one note about this: Don't be surprised if you remove the finish and find the wood is NOT walnut, but some softer yellow-white wood.
On the First Type Target grips for the cheaper guns, like the Trooper, Colt sometimes used this odd wood and put a very dark, almost black-brown stain on them with a dull oil-type finish.
Colt also sometimes used it on the Second Type grips for the Troopers, but with a more natural walnut color and a thin satin finish.
Whatever this wood is, it has a yellow-white color, is softer than American Walnut, and tends to get "fuzzy" when sanding or checkering.
I'm about 99% sure those are Colt factory First Type Target grips with the checkering sanded off.
First, note the position of the Silver medallions.
The medallions are placed just slightly higher and farther forward on First Type grips, and I've never seen a non-Colt copy position them there.
Second, note the slightly rounded edges. This is a classic sign of a sand job.
Here's a pair of original un-sanded First Type grips.
Note the position of the medallion:

Here's a pair of Second Type.
Note how the medallion is moved down and back slightly.
Every Colt grip of this type and later, and all copies I've seen position the medallion here:

What you could do is have someone re-checker the grips with the original type checkering to restore them to original form.
This would be a lot cheaper than trying to find and afford a set of original First Types.
However one note about this: Don't be surprised if you remove the finish and find the wood is NOT walnut, but some softer yellow-white wood.
On the First Type Target grips for the cheaper guns, like the Trooper, Colt sometimes used this odd wood and put a very dark, almost black-brown stain on them with a dull oil-type finish.
Colt also sometimes used it on the Second Type grips for the Troopers, but with a more natural walnut color and a thin satin finish.
Whatever this wood is, it has a yellow-white color, is softer than American Walnut, and tends to get "fuzzy" when sanding or checkering.