As noted above, the instrument manufacturers usually have fine tuned their procedures for common models, and it's sensible to have them perform the IQ/OQ as part of the installation.
If you operate in a regulated environment and have facility to easily perform the tests, then you can do that. However, you must ensure that a suitable process is followed, and approved by QA in advance of performing the steps. Most vendors provide their documents, so you can perform the tests, PROVIDED you are demonstrated and documented as skilled/trained to perform those tests!.
In other words, for an IQ, the vendor ( or somebody ) should have provided documented training to show that you are competent to perform the IQ/OQ for that instrument. If you aren't, the documents can be used as toilet paper. In reality, I suspect only multi-instrument site can justify the expense of having trained people for IQ/OQ to regulatory standards.
You should already have gone through the Design Qualification/preparing a User Requirement Specification for the HPLC before selecting the vendor, and also used that opportunity to ensure the total package price ( including training and IQ/OQ ) is competitive.
There is a problem with bespoke or less common systems, the vendor usually has to adapt their documents, and the cost of adding deviations can be quite large. You may be better to document the IQ/OQ, and perform the tests, depending on the value you assign to your time, and the skills of the local vendor.
Remember, in-house qualifications have to be performed by people whose experience and training are suitable, obvious and documented. It's the first item on most audit lists - " show me the training records of the person who performed the work ".
Bruce Hamilton