For many surface mount resistor products, there is a defined top mark format given by the manufacturer. In other cases, there may not be any marking. Small package/case sizes often do not have top marks, for example. However, it is not common to find surface mount resistors where the top mark is visible on some parts, but not on others, within the same series.
CTS Resistor Products manufactures some resistor arrays that do not have consistent marking. The 740 series is an example: [click here https://www.digikey.com/short/zd209z ]. Product Index > Resistors > Resistor Networks, Arrays > Series Filter: 740
Although the 74x datasheet shows top mark examples for 3-digit and 4-Digit formats (page 06), it also lists a few examples that may or may not have marking: [click here https://www.ctscorp.com/wp-content/uploads/74x.pdf ].
Are these parts the same with or without marking? Yes. The disparity in top marking is simply due to different factory locations. Some include marking as part of the manufacturing process, and some do not. There is no difference in the form or function of the product.