1. The Glass Itself:
* Tint: Original 1964 Corvette rear windows were *not* tinted. Any tint strongly suggests a replacement.
* GM Markings: Look for etched markings on the glass itself. These markings might be faint and difficult to see, but genuine GM glass often has them. However, their absence doesn't automatically mean it's not original; markings could have worn away.
* Thickness and Quality: Original glass should exhibit consistent thickness and quality. Examine for imperfections like waves, bubbles, or inconsistencies that might indicate aftermarket or replacement glass.
* Edge Condition: Look closely at the edges of the glass. Replacement windows might have slightly different edge treatments compared to originals.
2. The Installation:
* Seal: Examine the rubber seal around the window. Original seals will often show age and wear, but an extremely well-preserved seal might raise suspicion. A perfectly new seal suggests replacement.
* Body Interaction: The fit between the window and the body should be precise. Gaps, misalignments, or evidence of forcing suggest a replacement.
* Fasteners: Examine the screws or clips used to hold the window in place. Are they original or replacements? Original hardware will typically show signs of age and patina consistent with the car's overall condition.
3. Documentation:
* Original Build Sheet: If the car's original build sheet (if you have one) specifies the window options, this will be the most definitive proof.
* Previous Owner Records: Service records, receipts, or other documentation from previous owners might mention a window replacement.
4. Expert Consultation:
* Corvette Restoration Specialist: A reputable Corvette restoration specialist with experience in 1964 models can often identify original components. They'll have experience examining details that are difficult for the average person to discern.
Important Considerations:
* Condition of the car: If the car is heavily restored, it's much more likely that the rear window has been replaced at some point.
* No guarantees: Even with careful examination, there's no 100% guarantee you can determine originality. Many factors contribute to the difficulty of this assessment.
In summary, determining originality requires a detailed examination of the glass itself, the installation, and any available documentation. Consultation with a Corvette restoration specialist is highly recommended for the best chance of achieving a conclusive answer.
