Due to antitrust legislation, API standards never require an organization to purchase items from an API-certified manufacturer.

You can use bolting from a local vendor which meets all the requirements of API 20E. One of the requirements of API 20E is that bolting be marked "20E1" for BSL-1, "20E2" for BSL-2, or "20E3" for BSL-3, in addition to the marking required by the relevant ASTM specification. This marking is required to meet the API 6A and 20E requirements. However, the API monogram and "API" are not required to be marked on the bolts.

You will likely be required to provide evidence that the bolting meets API 20E. Most auditors and customers will readily accept bolting from an API-certified manufacturer based on the bolting marking and test report. Auditors and customers might be more skeptical and require more documentation/evidence of 20E-conformance for a non-certified manufacturer, but there is not clear guidance on the level of evidence required.

API 20E is complex and difficult. Normal bolting can not simply be upgraded to 20E bolting by inspection after manufacture - there are many requirements in 20E for qualification of bolting and process control by the manufacturer. I've experienced local, non-certified bolting vendors claim to meet all the requirements of API 20E, but then provide bolting and documentation which obviously did not meet in many aspects. If you use a non-certified manufacturer for 20E bolting, I strongly recommend that you carefully review and maintain evidence that they meet 20E.

Thanks jmec87 ...

Technically you can purchase from another vendor but it is a headache on the documentation end. We (Spring Bolt) are certified, but before we were most customers would not accept bolting that was not monogram. So we took the plunge, spend the money, and got our licenses (API Q1, 20E and now 20F)