Off the top of my head I do not recall a 625 with a ported barrel.

Pictures and more information would be nice.

Which engineering/production change (i.e. dash number) is it? What grips or stocks?

A 625 in a 3" barrel would be very desirable, especially in .45 Colt. 90% condition on a stainless S&W can frequently be easily improved without much effort or cost.

The SCSW 4th edition cites the following values for the Model 625:
$1000 ANIB
$750 Excellent
$600 Very Good

The revolver you describe might take a hit in value for the ported barrel but that would likely be offset by the highly desirable 3" barrel. The stocks/grips on the gun could also increase the value for example finger groove Combat stocks would likely increase the value. Pictures and more details would help members give you a better idea of value.

S&W did make the Model 625 with a 3" barrel.
Here are some of the 3" Model 625 product codes:
100923, 625-2, marked Model of 1989, circa 1989

100926, 625-4, Lew Horton Classic Snub, circa 1991

148121, 625-7, .45 Colt, Lew Horton, Colt "Classic Carry, circa 1998

149141, two-tone satin

170071 Performance Center

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