Installer already has both. Shoulder occupies the sample fixture's clearance. Sending the complete marked comparison directly to technical support.

Ask whether they can supply the originally confirmed adapter as well, because you should not have to redesign the sample fixture simply to discover what their substitute changes.

Technical contact acknowledges the clearance conflict. Offered to machine the shoulder locally. No revised drawing or assessment included.

That proposal needs design ownership and an identified final requirement before anyone prices or performs machining. A photograph with a bit circled is not enough for the person taking responsibility for the adapter.

Declined local machining without that information. Asked again for the confirmed adapter or a complete assessed alternative.

Did the seller explain the label suffix, or only acknowledge that the shoulder is different?

Suffix identifies their alternative adapter package. They now admit it was substituted without checking our confirmed fixture drawing.

Then keep the original supply request tied to that acknowledgement, rather than reopening whether the fixture ought to accommodate it; have they answered availability of the confirmed part?

Original part available. Replacement offer now names the drawing revision and includes the required fixing pack. Installer checking offer details.

Give receiving that exact list too, so the arrival of a plate alone does not close the missing fixing pack by enthusiasm.

And retain the substituted adapter's identity under the return arrangement. It should not become an unlabelled spare beside the correct one.

Replacement received with fixings. Installer checked the complete assembly against the agreed revision, including fixture clearance. Mismatch closed; substitute separated for return.

Did the replacement reference reach the equipment and spare-parts list as well, so the next order does not repeat their substitution?