I read a ton about injection molding today. Even though the mold itself is exactly the same as the original Chipco's, the final products from different manufacturers will have different barrel lengths depending upon the type of plastic being used, the amount of time and method to cool down the plastic, the amount of crystallization that the manufacturer desires in the product, and the duration the plastic is kept above its glass transition temperature (these are not unique independent variables of each other, but altered to attain desired compromise between durability, rigidity, and size). Manufacturers often use the same molds and adjust temperatures to attain desired changes in sizes. This is likely the chosen path here to use the same mold for different sized barrels as well. There is plenty of literature I found on this topic due to the necessity to size plastic gearing or other parts with small tolerances for changes in wear dimensions if replacing just one cog and the other is smaller, for example.
Therefore, identifying logos and markings will unfortunately not help to verify the barrel lengths and fit of the rack before purchase. So, the best bet to find an ideal fit for any specific chipset is likely to come from other chippers' experience found in these forums.