This paper analyses a collection of engraved plaques from Golfo San Matías (Río Negro province) in order to assess design recurrences which might point to the presence of ornamentation rules and/or visual information coding among the hunter-gatherer peoples who produced and used them. Then, 170 plaques from Patagonia and other regions of Argentina are systematically compared using the presence of shared motif types as the main criterion. Data are assessed using a theoretical model with expectations which link design variability/standardization, ornamental laxity/structuration and informational heterogeneity/redundancy. Results show that plaques display low design standardization, which is compatible with a low redundancy communicative function (heterogeneous content) and/or with an ornamental function with lax rules. Moreover, the shared repertoires document several inter-regional links, which are verified using different lines of archaeological evidence. [ABSTRACT FROM AUTHOR]