While there are some general guidelines typically used, SOX controls are very individualized between organizations. If one of your organization's key objectives (and therefore key control) within commercial loans is adequate collateral and adequate documentation (and these typically are key objectives), then yes, this would be SOX Rule 404 control.
There may or may not be a requirement that a person independent from the lending function perform these checks. This would depend a lot on how this fits within your other lending controls.
I know that seems like a wishy-washy answer, but SOX 404 compliance is not a published laundry list of "must do" items that fits all organizations, but a documentation of how your organization achieves its internal control objectives. If the objectives you talk about have been identified as key, then you need key controls somewhere to achieve this objective, and if you decide this check process is the key control, then yes it is an integral part of your SOX documentation. If you decide that you don't need segregation of duty (i.e.-person external to the loan function doing the check), you need to convince your auditor that you achieve the results without segregation. If you do decide you need segregation, then someone outside the loan function will need to perform these checks.